Portable electronic devices such as wireless communication devices (e.g., mobile cellular phones) typically have input keys, such as buttons and navigation keys, for allowing a user to enter data and issue commands. For certain applications, such as for video games for example, it is desirable to provide controls that allow the user to rapidly issue commands and to provide greater dexterity in controlling the input keys. Control arms (e.g., joysticks) are used for such purposes.
Several challenges are presented in any design that integrates a control arm with a portable electronic device. As discussed below, these challenges are even greater where the device is a wireless communication device due to certain design constraints. One common problem is the interference created by the control arm when not in use. For example, in the case of a portable gaming device, a protruding control arm may necessitate an oversized protective shell for transport. In the case of a personal digital assistant (“PDA”), a protruding control arm may preclude carrying the PDA in one's pocket. In the case of a laptop computer, a protruding control arm may interfere with keyboard entry. Finally, in the case of a mobile phone, a protruding control arm may interfere with the user's positioning of the phone while making a call, or may be a liability to being damaged during normal phone use, i.e. a dropped phone.
One known implementation is to provide a control arm that is detachable from (i.e., non-integral with) the device. However, this approach disadvantageously requires the user to mount and dismount the control arm as needed, and further requires means for securing or stowing the control arm when detached from the device. Such an implementation allows the control arm to easily become lost.
Another known implementation is to provide a control arm that is recessed into the device. A number of computer laptops use this type of control arm as a alternative to the computer mouse. However, this approach disadvantageously limits the user's ability to manipulate the control arm. For example, in this configuration the user typically cannot grasp the control arm and is limited to one-finger operation.
Another known implementation is to provide a control arm that can be pushed down into the device. Similar to the recessed implementation, prior approaches have sacrificed other desirable attributes of the device in order to include this functionality. For example, with respect to devices having an integrated, retractable control arm, prior approaches include lowering the control arm into a cavity within the device. In order to accommodate this linear motion, valuable space (typically along device's smallest dimension) must be compromised. In many cases, a portable electronic device will include a printed circuit board (“PCB”) that intersects the travel path of the stowed control arm. Accordingly, a hole in the PCB must be created in order to provide a path for the control arm. In addition to loss of valuable space within the device, a number of drawbacks are presented by requiring holes to be present in PCBs, as is known in the art.
Some existing implementations involving foldable mobile cellular phones call for cumbersome mechanisms that automatically extend and retract the control arm, depending on whether the foldable device is opened or closed. This arrangement is of limited utility since it requires additional components, increases device complexity and costs, requires additional occupation of valuable space, and does not permit a user to retract the control arm while the foldable device is open.
Accordingly, there exists a strong need in the art for a retractable control arm for a portable electronic device which addresses and resolves one or more of the above mentioned problems.